Generally, electric vehicles differ from conventional motor vehicles because electric vehicles are driven, at least in part, using one or more battery-powered electric motors. Conventional motor vehicles, by contrast, rely exclusively on an internal combustion engine to drive the vehicle. Electric vehicles may use electric motors instead of, or in addition to, the internal combustion engine.
Example electric vehicles include hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), fuel cell vehicles, fuel cell electric vehicles, and battery electric vehicles (BEVs). A BEV includes an electric motor, wherein the energy source for the motor is a battery that is re-chargeable from an external electric grid. A HEV includes an internal combustion engine and an electric motor, wherein the energy source for the engine is fuel and the energy source for the motor is a battery. A PHEV is like a HEV, but the PHEV has a larger capacity battery that is rechargeable from the external electric grid.
Electric vehicles commonly require the usage of various specialized vehicle components, such as high voltage (HV) battery systems. HV battery systems for electric vehicles typically include one or more high voltage batteries to provide the energy required by the drive systems of such vehicles.
Owing to their high voltage, high specific energy, high energy density, low self-discharge rate, long cycle life and wide temperature operational range, prismatic lithium-ion (Li-ion) cells are widely used in HV battery systems for use in BEV, HEV, and PHEV. A prismatic Li-ion cell 1a typically includes a hard shell case 2 (sometimes referred to as a “can”) that encloses a cell element 5 having a multi-layered material that is folded and/or wound and/or stacked to provide the cell element 5. Because of the shape of the cell element 5 that it contains, the case 2 typically has a face 3 that is longer than its side 4. The depicted prismatic Li-ion cell 1a has a top cover 8 and a bottom cover 7. The top cover 8 typically includes a negative electrical terminal 9a and positive electrical terminal 9b. 
To create battery systems for use in many electric automobiles, a plurality of individual prismatic Li-ion cells can be arranged together, typically in a face-to-face configuration (sometime referred to as a front-to-back configuration), to form an array 1b of individual prismatic Li-ion cells. However, such arrays can be heavy and often suffer from thermal and pressure heterogeneity. Moreover, the individual cells within such arrays are susceptible to misalignment, and non-uniform compressive forces, which can adversely affect the electrical connections between the individual cells and lead to other problems.
It is desirable to provide improved battery systems that address one or more of the deficiencies associated battery systems that are composed a plurality of single battery cells.